Stencil for copying purposes



Patented Sept. 15, 1931 UNITED STATES PATENT OFFICIE MAX 'DESENISS, OF HAMBURG, GERMANY, ASSIGNOR T ALEXANDER FEU'RICH, OF HAMBURG, GERMANY STENCIL FOR COPYING PURPOSES No Drawing. Application filed October 26, 1929, Serial No. 402,788, and in Germany July 24, 1928.

My invention relates to improvements in stencils for copying purposes.

Stencils for copying purposes consist of a porous foundation and a coating capable i of being perforated, the said coating ordinarily consisting of a paraflin, albuminous substances, caoutchouc, resins and cellulose esters. I have discovered that excellent stencilswhich are durable and which can be u) printed upon in a very satisfactory way are produced When coating the paper at one or both sides with thin layers of products of chlorination of caoutchouc. As a carrier for the said coating I prefer to use a paper of '5 coarse pores, such as Japan paper.

For .imparting elasticity and softness to the stencil I add suitable substances to .the coating, such for example as castor oil, palatinol, and the like. Further, I may add filling media, such as talcum or zinc White.

In the manufacture of the sheet I prepare a solution of 10 grammes of chlorinated .ca-outchouc in 120 grammes of benzene, and to the said solution I may add grammes of a suitable softening medium, such as castor oil, phthalic acid ester or the like and 70 grammes of filling matter such as talcum or zinc white, the said solution being spread on Japan paper. After drying the sheet is ready for use, and it has a high strength a ainst creasing.

It will be understood that the chlorine content of the chlorinated caoutchouc may I be varied as desired, it being only necessary to add sufiicient softening material to compensate for the amount of chlorine present so that the coating substance may be sufficiently soft to receive the impression of the type or other perforating member.

I claim:

1. The herein described sheet for making stencils for copying purposes, comprising a porous foundation having a coating of a product of chlorination of caoutchouc and a softening agent.

signature.

' DR. MAX DESENISS. 

